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<a href="ipc__shm_2src_2ipc_2transport_2struc_2shm_2util_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow-IPC: Shared Memory</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span> </div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span><span class="preprocessor">#include &quot;<a class="code" href="transport_2struc_2shm_2shm__fwd_8hpp.html">ipc/transport/struc/shm/shm_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="util__fwd_8hpp.html">ipc/util/util_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span> </div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceipc_1_1transport_1_1struc_1_1shm.html">ipc::transport::struc::shm</a></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span>{</div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span> </div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment">// Implementations.</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno"><a class="line" href="namespaceipc_1_1transport_1_1struc_1_1shm.html#ab592ce6eddbe24c57dc71f34018fb042">   28</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceipc_1_1transport_1_1struc_1_1shm.html#ab592ce6eddbe24c57dc71f34018fb042">capnp_set_lent_shm_handle</a>(<a class="code hl_typedef" href="namespaceipc_1_1transport_1_1struc_1_1shm_1_1classic.html#abfde278018c84aa1542475e9a4089c29">schema::ShmHandle::Builder</a>* shm_handle_root,</div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span>                               <span class="keyword">const</span> flow::util::Blob_sans_log_context&amp; lend_result)</div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span>{</div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span>  <span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">util::Blob_mutable</a>;</div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span> </div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span>  assert((!lend_result.empty()) &amp;&amp; <span class="stringliteral">&quot;Did you account for shm_session.lend_object() returning empty blob &quot;</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span>                                     <span class="stringliteral">&quot;(likely session down)?&quot;</span>);</div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span>  assert(shm_handle_root);</div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span> </div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span>  <span class="keyword">const</span> <span class="keyword">auto</span> n = lend_result.size();</div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span> </div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span>  <span class="comment">/* Avoid wasting internal serialization space if already init...()ed.</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment">   * (capnp docs state that initX() when `x` is already initX()ed will zero but otherwise leave the previously</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment">   * initialized field inside the serialization.  capnp does not reuse such space for reasons (trade-off).) */</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span>  <span class="keyword">const</span> <span class="keywordtype">bool</span> field_inited_already = shm_handle_root-&gt;hasSerialization();</div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span>  <span class="keyword">auto</span> capnp_blob_builder = field_inited_already ? shm_handle_root-&gt;getSerialization()</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span>                                                 : shm_handle_root-&gt;initSerialization(n);</div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span>  assert(((!field_inited_already) || (capnp_blob_builder.size() == n))</div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span>         &amp;&amp; <span class="stringliteral">&quot;Please only pass-in uninitialized ShmHandle field or one filled-out by this same function earlier.&quot;</span>);</div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span> </div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span>  lend_result.sub_copy(lend_result.begin(), <a class="code hl_typedef" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">Blob_mutable</a>(capnp_blob_builder.begin(), n));</div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span>} <span class="comment">// capnp_set_lent_shm_handle()</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span> </div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno"><a class="line" href="namespaceipc_1_1transport_1_1struc_1_1shm.html#adb38fe88cfd5e758ef52c482d2902669">   51</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceipc_1_1transport_1_1struc_1_1shm.html#adb38fe88cfd5e758ef52c482d2902669">capnp_get_shm_handle_to_borrow</a>(<span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1transport_1_1struc_1_1shm_1_1classic.html#af94f8698ca62a84d6366aaa931375d41">schema::ShmHandle::Reader</a>&amp; shm_handle_root,</div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span>                                    flow::util::Blob_sans_log_context* arg_to_borrow)</div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span>{</div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span>  <span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">util::Blob_const</a>;</div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span> </div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span>  assert(arg_to_borrow);</div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span> </div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span>  <span class="keyword">const</span> <span class="keyword">auto</span> capnp_blob_reader = shm_handle_root.getSerialization();</div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span>  arg_to_borrow-&gt;assign_copy(<a class="code hl_typedef" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">Blob_const</a>(capnp_blob_reader.begin(), capnp_blob_reader.size()));</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span> </div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span>  assert(!arg_to_borrow-&gt;empty());</div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span>} <span class="comment">// capnp_get_shm_handle_to_borrow()</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span> </div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span>} <span class="comment">// namespace ipc::transport::struc::shm</span></div>
<div class="ttc" id="anamespaceipc_1_1transport_1_1struc_1_1shm_1_1classic_html_abfde278018c84aa1542475e9a4089c29"><div class="ttname"><a href="namespaceipc_1_1transport_1_1struc_1_1shm_1_1classic.html#abfde278018c84aa1542475e9a4089c29">ipc::transport::struc::shm::classic::Builder</a></div><div class="ttdeci">Builder&lt; ipc::shm::classic::Pool_arena &gt; Builder</div><div class="ttdoc">Convenience alias: transport::struc::shm::Builder that works with boost.ipc.shm pools from ipc::shm::...</div><div class="ttdef"><b>Definition:</b> <a href="transport_2struc_2shm_2classic_2classic__fwd_8hpp_source.html#l00036">classic_fwd.hpp:36</a></div></div>
<div class="ttc" id="anamespaceipc_1_1transport_1_1struc_1_1shm_1_1classic_html_af94f8698ca62a84d6366aaa931375d41"><div class="ttname"><a href="namespaceipc_1_1transport_1_1struc_1_1shm_1_1classic.html#af94f8698ca62a84d6366aaa931375d41">ipc::transport::struc::shm::classic::Reader</a></div><div class="ttdeci">Reader&lt; ipc::shm::classic::Pool_arena &gt; Reader</div><div class="ttdoc">Convenience alias: transport::struc::shm::Reader that works with boost.ipc.shm pools from ipc::shm::c...</div><div class="ttdef"><b>Definition:</b> <a href="transport_2struc_2shm_2classic_2classic__fwd_8hpp_source.html#l00039">classic_fwd.hpp:39</a></div></div>
<div class="ttc" id="anamespaceipc_1_1transport_1_1struc_1_1shm_html"><div class="ttname"><a href="namespaceipc_1_1transport_1_1struc_1_1shm.html">ipc::transport::struc::shm</a></div><div class="ttdoc">Segregates zero-copy/SHM implementations of concepts residing in parent namespace ipc::transport::str...</div><div class="ttdef"><b>Definition:</b> <a href="capnp__msg__builder_8hpp_source.html#l00029">capnp_msg_builder.hpp:30</a></div></div>
<div class="ttc" id="anamespaceipc_1_1transport_1_1struc_1_1shm_html_ab592ce6eddbe24c57dc71f34018fb042"><div class="ttname"><a href="namespaceipc_1_1transport_1_1struc_1_1shm.html#ab592ce6eddbe24c57dc71f34018fb042">ipc::transport::struc::shm::capnp_set_lent_shm_handle</a></div><div class="ttdeci">void capnp_set_lent_shm_handle(schema::ShmHandle::Builder *shm_handle_root, const flow::util::Blob_sans_log_context &amp;lend_result)</div><div class="ttdoc">Utility that saves the result of a Shm_session1::lend_object&lt;T&gt;(const shared_ptr&lt;T&gt;&amp;) result into the...</div><div class="ttdef"><b>Definition:</b> <a href="ipc__shm_2src_2ipc_2transport_2struc_2shm_2util_8cpp_source.html#l00028">util.cpp:28</a></div></div>
<div class="ttc" id="anamespaceipc_1_1transport_1_1struc_1_1shm_html_adb38fe88cfd5e758ef52c482d2902669"><div class="ttname"><a href="namespaceipc_1_1transport_1_1struc_1_1shm.html#adb38fe88cfd5e758ef52c482d2902669">ipc::transport::struc::shm::capnp_get_shm_handle_to_borrow</a></div><div class="ttdeci">void capnp_get_shm_handle_to_borrow(const schema::ShmHandle::Reader &amp;shm_handle_root, flow::util::Blob_sans_log_context *arg_to_borrow)</div><div class="ttdoc">Utility that's the reverse of capnp_set_lent_shm_handle() to be invoked on the deserializing side.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__shm_2src_2ipc_2transport_2struc_2shm_2util_8cpp_source.html#l00051">util.cpp:51</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a6cb62ae434900f3a8915b33ec5d61a96"><div class="ttname"><a href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">ipc::util::Blob_mutable</a></div><div class="ttdeci">boost::asio::mutable_buffer Blob_mutable</div><div class="ttdoc">Short-hand for an mutable blob somewhere in memory, stored as exactly a void* and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00140">util_fwd.hpp:140</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ae0be7edba7e30ffa3f8b742af621f2ab"><div class="ttname"><a href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">ipc::util::Blob_const</a></div><div class="ttdeci">boost::asio::const_buffer Blob_const</div><div class="ttdoc">Short-hand for an immutable blob somewhere in memory, stored as exactly a void const * and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00134">util_fwd.hpp:134</a></div></div>
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